// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc.  All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package com.google.protobuf;

import com.google.protobuf.Descriptors.EnumValueDescriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;
import com.google.protobuf.Descriptors.OneofDescriptor;
import com.google.protobuf.Internal.EnumLite;

import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * A partial implementation of the {@link Message} interface which implements as many methods of
 * that interface as possible in terms of other methods.
 *
 * @author kenton@google.com Kenton Varda
 */
public abstract class AbstractMessage
        // TODO(dweis): Update GeneratedMessage to parameterize with MessageType and BuilderType.
        extends AbstractMessageLite implements Message {

    @Override
    public boolean isInitialized() {
        return MessageReflection.isInitialized(this);
    }

    /**
     * Interface for the parent of a Builder that allows the builder to communicate invalidations back
     * to the parent for use when using nested builders.
     */
    protected interface BuilderParent {

        /**
         * A builder becomes dirty whenever a field is modified -- including fields in nested builders
         * -- and becomes clean when build() is called. Thus, when a builder becomes dirty, all its
         * parents become dirty as well, and when it becomes clean, all its children become clean. The
         * dirtiness state is used to invalidate certain cached values.
         *
         * <p>To this end, a builder calls markDirty() on its parent whenever it transitions from clean
         * to dirty. The parent must propagate this call to its own parent, unless it was already dirty,
         * in which case the grandparent must necessarily already be dirty as well. The parent can only
         * transition back to "clean" after calling build() on all children.
         */
        void markDirty();
    }

    /**
     * Create a nested builder.
     */
    protected Message.Builder newBuilderForType(BuilderParent parent) {
        throw new UnsupportedOperationException("Nested builder is not supported for this type.");
    }


    @Override
    public List<String> findInitializationErrors() {
        return MessageReflection.findMissingFields(this);
    }

    @Override
    public String getInitializationErrorString() {
        return MessageReflection.delimitWithCommas(findInitializationErrors());
    }

    /**
     * TODO(jieluo): Clear it when all subclasses have implemented this method.
     */
    @Override
    public boolean hasOneof(OneofDescriptor oneof) {
        throw new UnsupportedOperationException("hasOneof() is not implemented.");
    }

    /**
     * TODO(jieluo): Clear it when all subclasses have implemented this method.
     */
    @Override
    public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
        throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
    }

    @Override
    public final String toString() {
        return TextFormat.printer().printToString(this);
    }

    @Override
    public void writeTo(final CodedOutputStream output) throws IOException {
        MessageReflection.writeMessageTo(this, getAllFields(), output, false);
    }

    protected int memoizedSize = -1;

    @Override
    int getMemoizedSerializedSize() {
        return memoizedSize;
    }

    @Override
    void setMemoizedSerializedSize(int size) {
        memoizedSize = size;
    }

    @Override
    public int getSerializedSize() {
        int size = memoizedSize;
        if (size != -1) {
            return size;
        }

        memoizedSize = MessageReflection.getSerializedSize(this, getAllFields());
        return memoizedSize;
    }

    @Override
    public boolean equals(final Object other) {
        if (other == this) {
            return true;
        }
        if (!(other instanceof Message)) {
            return false;
        }
        final Message otherMessage = (Message) other;
        if (getDescriptorForType() != otherMessage.getDescriptorForType()) {
            return false;
        }
        return compareFields(getAllFields(), otherMessage.getAllFields())
                && getUnknownFields().equals(otherMessage.getUnknownFields());
    }

    @Override
    public int hashCode() {
        int hash = memoizedHashCode;
        if (hash == 0) {
            hash = 41;
            hash = (19 * hash) + getDescriptorForType().hashCode();
            hash = hashFields(hash, getAllFields());
            hash = (29 * hash) + getUnknownFields().hashCode();
            memoizedHashCode = hash;
        }
        return hash;
    }

    private static ByteString toByteString(Object value) {
        if (value instanceof byte[]) {
            return ByteString.copyFrom((byte[]) value);
        } else {
            return (ByteString) value;
        }
    }

    /**
     * Compares two bytes fields. The parameters must be either a byte array or a ByteString object.
     * They can be of different type though.
     */
    private static boolean compareBytes(Object a, Object b) {
        if (a instanceof byte[] && b instanceof byte[]) {
            return Arrays.equals((byte[]) a, (byte[]) b);
        }
        return toByteString(a).equals(toByteString(b));
    }

    /**
     * Converts a list of MapEntry messages into a Map used for equals() and hashCode().
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    private static Map convertMapEntryListToMap(List list) {
        if (list.isEmpty()) {
            return Collections.emptyMap();
        }
        Map result = new HashMap<>();
        Iterator iterator = list.iterator();
        Message entry = (Message) iterator.next();
        Descriptors.Descriptor descriptor = entry.getDescriptorForType();
        Descriptors.FieldDescriptor key = descriptor.findFieldByName("key");
        Descriptors.FieldDescriptor value = descriptor.findFieldByName("value");
        Object fieldValue = entry.getField(value);
        if (fieldValue instanceof EnumValueDescriptor) {
            fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
        }
        result.put(entry.getField(key), fieldValue);
        while (iterator.hasNext()) {
            entry = (Message) iterator.next();
            fieldValue = entry.getField(value);
            if (fieldValue instanceof EnumValueDescriptor) {
                fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
            }
            result.put(entry.getField(key), fieldValue);
        }
        return result;
    }

    /**
     * Compares two map fields. The parameters must be a list of MapEntry messages.
     */
    @SuppressWarnings({"rawtypes", "unchecked"})
    private static boolean compareMapField(Object a, Object b) {
        Map ma = convertMapEntryListToMap((List) a);
        Map mb = convertMapEntryListToMap((List) b);
        return MapFieldLite.equals(ma, mb);
    }

    /**
     * Compares two set of fields. This method is used to implement {@link
     * AbstractMessage#equals(Object)} and {@link AbstractMutableMessage#equals(Object)}. It takes
     * special care of bytes fields because immutable messages and mutable messages use different Java
     * type to represent a bytes field and this method should be able to compare immutable messages,
     * mutable messages and also an immutable message to a mutable message.
     */
    static boolean compareFields(Map<FieldDescriptor, Object> a, Map<FieldDescriptor, Object> b) {
        if (a.size() != b.size()) {
            return false;
        }
        for (FieldDescriptor descriptor : a.keySet()) {
            if (!b.containsKey(descriptor)) {
                return false;
            }
            Object value1 = a.get(descriptor);
            Object value2 = b.get(descriptor);
            if (descriptor.getType() == FieldDescriptor.Type.BYTES) {
                if (descriptor.isRepeated()) {
                    List list1 = (List) value1;
                    List list2 = (List) value2;
                    if (list1.size() != list2.size()) {
                        return false;
                    }
                    for (int i = 0; i < list1.size(); i++) {
                        if (!compareBytes(list1.get(i), list2.get(i))) {
                            return false;
                        }
                    }
                } else {
                    // Compares a singular bytes field.
                    if (!compareBytes(value1, value2)) {
                        return false;
                    }
                }
            } else if (descriptor.isMapField()) {
                if (!compareMapField(value1, value2)) {
                    return false;
                }
            } else {
                // Compare non-bytes fields.
                if (!value1.equals(value2)) {
                    return false;
                }
            }
        }
        return true;
    }

    /**
     * Calculates the hash code of a map field. {@code value} must be a list of MapEntry messages.
     */
    @SuppressWarnings("unchecked")
    private static int hashMapField(Object value) {
        return MapFieldLite.calculateHashCodeForMap(convertMapEntryListToMap((List) value));
    }

    /**
     * Get a hash code for given fields and values, using the given seed.
     */
    @SuppressWarnings("unchecked")
    protected static int hashFields(int hash, Map<FieldDescriptor, Object> map) {
        for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
            FieldDescriptor field = entry.getKey();
            Object value = entry.getValue();
            hash = (37 * hash) + field.getNumber();
            if (field.isMapField()) {
                hash = (53 * hash) + hashMapField(value);
            } else if (field.getType() != FieldDescriptor.Type.ENUM) {
                hash = (53 * hash) + value.hashCode();
            } else if (field.isRepeated()) {
                List<? extends EnumLite> list = (List<? extends EnumLite>) value;
                hash = (53 * hash) + Internal.hashEnumList(list);
            } else {
                hash = (53 * hash) + Internal.hashEnum((EnumLite) value);
            }
        }
        return hash;
    }

    /**
     * Package private helper method for AbstractParser to create UninitializedMessageException with
     * missing field information.
     */
    @Override
    UninitializedMessageException newUninitializedMessageException() {
        return Builder.newUninitializedMessageException(this);
    }

    // =================================================================

    /**
     * A partial implementation of the {@link Message.Builder} interface which implements as many
     * methods of that interface as possible in terms of other methods.
     */
    @SuppressWarnings("unchecked")
    public abstract static class Builder<BuilderType extends Builder<BuilderType>>
            extends AbstractMessageLite.Builder implements Message.Builder {
        // The compiler produces an error if this is not declared explicitly.
        // Method isn't abstract to bypass Java 1.6 compiler issue:
        //     http://bugs.java.com/view_bug.do?bug_id=6908259
        @Override
        public BuilderType clone() {
            throw new UnsupportedOperationException("clone() should be implemented in subclasses.");
        }

        /**
         * TODO(jieluo): Clear it when all subclasses have implemented this method.
         */
        @Override
        public boolean hasOneof(OneofDescriptor oneof) {
            throw new UnsupportedOperationException("hasOneof() is not implemented.");
        }

        /**
         * TODO(jieluo): Clear it when all subclasses have implemented this method.
         */
        @Override
        public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
            throw new UnsupportedOperationException("getOneofFieldDescriptor() is not implemented.");
        }

        /**
         * TODO(jieluo): Clear it when all subclasses have implemented this method.
         */
        @Override
        public BuilderType clearOneof(OneofDescriptor oneof) {
            throw new UnsupportedOperationException("clearOneof() is not implemented.");
        }

        @Override
        public BuilderType clear() {
            for (final Map.Entry<FieldDescriptor, Object> entry : getAllFields().entrySet()) {
                clearField(entry.getKey());
            }
            return (BuilderType) this;
        }

        @Override
        public List<String> findInitializationErrors() {
            return MessageReflection.findMissingFields(this);
        }

        @Override
        public String getInitializationErrorString() {
            return MessageReflection.delimitWithCommas(findInitializationErrors());
        }

        @Override
        protected BuilderType internalMergeFrom(AbstractMessageLite other) {
            return mergeFrom((Message) other);
        }

        @Override
        public BuilderType mergeFrom(final Message other) {
            return mergeFrom(other, other.getAllFields());
        }

        BuilderType mergeFrom(final Message other, Map<FieldDescriptor, Object> allFields) {
            if (other.getDescriptorForType() != getDescriptorForType()) {
                throw new IllegalArgumentException(
                        "mergeFrom(Message) can only merge messages of the same type.");
            }

            // Note:  We don't attempt to verify that other's fields have valid
            //   types.  Doing so would be a losing battle.  We'd have to verify
            //   all sub-messages as well, and we'd have to make copies of all of
            //   them to insure that they don't change after verification (since
            //   the Message interface itself cannot enforce immutability of
            //   implementations).
            // TODO(kenton):  Provide a function somewhere called makeDeepCopy()
            //   which allows people to make secure deep copies of messages.

            for (final Map.Entry<FieldDescriptor, Object> entry : allFields.entrySet()) {
                final FieldDescriptor field = entry.getKey();
                if (field.isRepeated()) {
                    for (final Object element : (List) entry.getValue()) {
                        addRepeatedField(field, element);
                    }
                } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
                    final Message existingValue = (Message) getField(field);
                    if (existingValue == existingValue.getDefaultInstanceForType()) {
                        setField(field, entry.getValue());
                    } else {
                        setField(
                                field,
                                existingValue
                                        .newBuilderForType()
                                        .mergeFrom(existingValue)
                                        .mergeFrom((Message) entry.getValue())
                                        .build());
                    }
                } else {
                    setField(field, entry.getValue());
                }
            }

            mergeUnknownFields(other.getUnknownFields());

            return (BuilderType) this;
        }

        @Override
        public BuilderType mergeFrom(final CodedInputStream input) throws IOException {
            return mergeFrom(input, ExtensionRegistry.getEmptyRegistry());
        }

        @Override
        public BuilderType mergeFrom(
                final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
                throws IOException {
            boolean discardUnknown = input.shouldDiscardUnknownFields();
            final UnknownFieldSet.Builder unknownFields =
                    discardUnknown ? null : UnknownFieldSet.newBuilder(getUnknownFields());
            while (true) {
                final int tag = input.readTag();
                if (tag == 0) {
                    break;
                }

                MessageReflection.BuilderAdapter builderAdapter =
                        new MessageReflection.BuilderAdapter(this);
                if (!MessageReflection.mergeFieldFrom(
                        input, unknownFields, extensionRegistry, getDescriptorForType(), builderAdapter, tag)) {
                    // end group tag
                    break;
                }
            }
            if (unknownFields != null) {
                setUnknownFields(unknownFields.build());
            }
            return (BuilderType) this;
        }

        @Override
        public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
            setUnknownFields(
                    UnknownFieldSet.newBuilder(getUnknownFields()).mergeFrom(unknownFields).build());
            return (BuilderType) this;
        }

        @Override
        public Message.Builder getFieldBuilder(final FieldDescriptor field) {
            throw new UnsupportedOperationException(
                    "getFieldBuilder() called on an unsupported message type.");
        }

        @Override
        public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
            throw new UnsupportedOperationException(
                    "getRepeatedFieldBuilder() called on an unsupported message type.");
        }

        @Override
        public String toString() {
            return TextFormat.printer().printToString(this);
        }

        /**
         * Construct an UninitializedMessageException reporting missing fields in the given message.
         */
        protected static UninitializedMessageException newUninitializedMessageException(
                Message message) {
            return new UninitializedMessageException(MessageReflection.findMissingFields(message));
        }

        /**
         * Used to support nested builders and called to mark this builder as clean. Clean builders will
         * propagate the {@link BuilderParent#markDirty()} event to their parent builders, while dirty
         * builders will not, as their parents should be dirty already.
         *
         * <p>NOTE: Implementations that don't support nested builders don't need to override this
         * method.
         */
        void markClean() {
            throw new IllegalStateException("Should be overridden by subclasses.");
        }

        /**
         * Used to support nested builders and called when this nested builder is no longer used by its
         * parent builder and should release the reference to its parent builder.
         *
         * <p>NOTE: Implementations that don't support nested builders don't need to override this
         * method.
         */
        void dispose() {
            throw new IllegalStateException("Should be overridden by subclasses.");
        }

        // ===============================================================
        // The following definitions seem to be required in order to make javac
        // not produce weird errors like:
        //
        // java/com/google/protobuf/DynamicMessage.java:203: types
        //   com.google.protobuf.AbstractMessage.Builder<
        //     com.google.protobuf.DynamicMessage.Builder> and
        //   com.google.protobuf.AbstractMessage.Builder<
        //     com.google.protobuf.DynamicMessage.Builder> are incompatible; both
        //   define mergeFrom(com.google.protobuf.ByteString), but with unrelated
        //   return types.
        //
        // Strangely, these lines are only needed if javac is invoked separately
        // on AbstractMessage.java and AbstractMessageLite.java.  If javac is
        // invoked on both simultaneously, it works.  (Or maybe the important
        // point is whether or not DynamicMessage.java is compiled together with
        // AbstractMessageLite.java -- not sure.)  I suspect this is a compiler
        // bug.

        @Override
        public BuilderType mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
            return (BuilderType) super.mergeFrom(data);
        }

        @Override
        public BuilderType mergeFrom(
                final ByteString data, final ExtensionRegistryLite extensionRegistry)
                throws InvalidProtocolBufferException {
            return (BuilderType) super.mergeFrom(data, extensionRegistry);
        }

        @Override
        public BuilderType mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
            return (BuilderType) super.mergeFrom(data);
        }

        @Override
        public BuilderType mergeFrom(final byte[] data, final int off, final int len)
                throws InvalidProtocolBufferException {
            return (BuilderType) super.mergeFrom(data, off, len);
        }

        @Override
        public BuilderType mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
                throws InvalidProtocolBufferException {
            return (BuilderType) super.mergeFrom(data, extensionRegistry);
        }

        @Override
        public BuilderType mergeFrom(
                final byte[] data,
                final int off,
                final int len,
                final ExtensionRegistryLite extensionRegistry)
                throws InvalidProtocolBufferException {
            return (BuilderType) super.mergeFrom(data, off, len, extensionRegistry);
        }

        @Override
        public BuilderType mergeFrom(final InputStream input) throws IOException {
            return (BuilderType) super.mergeFrom(input);
        }

        @Override
        public BuilderType mergeFrom(
                final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
            return (BuilderType) super.mergeFrom(input, extensionRegistry);
        }

        @Override
        public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
            return super.mergeDelimitedFrom(input);
        }

        @Override
        public boolean mergeDelimitedFrom(
                final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
            return super.mergeDelimitedFrom(input, extensionRegistry);
        }
    }

    /**
     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
     * generated code.
     */
    @Deprecated
    protected static int hashLong(long n) {
        return (int) (n ^ (n >>> 32));
    }
    //

    /**
     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
     * generated code.
     */
    @Deprecated
    protected static int hashBoolean(boolean b) {
        return b ? 1231 : 1237;
    }
    //

    /**
     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
     * generated code.
     */
    @Deprecated
    protected static int hashEnum(EnumLite e) {
        return e.getNumber();
    }
    //

    /**
     * @deprecated from v3.0.0-beta-3+, for compatibility with v2.5.0 and v2.6.1
     * generated code.
     */
    @Deprecated
    protected static int hashEnumList(List<? extends EnumLite> list) {
        int hash = 1;
        for (EnumLite e : list) {
            hash = 31 * hash + hashEnum(e);
        }
        return hash;
    }
}
